1. Field of the Invention
The general field of the present invention relates to static structures, i.e., buildings, and to pipes and tubular conduits; more particularly to the use of a hollow form or core in the forming of a cavity or cell in a concrete slab and to providing the end of a pipe with a plug or end protector; most specifically to such a form preserving space about a hub type drain in the pouring of a concrete slab floor which includes a threaded end protector.
2. General Background
Hub type drains typically possess a drain collar seated in the open top end of the drain and secured to the same with a plurality of bolts arranged concentrically about a central threaded bore into which an adjustable strainer may be threaded. When a concrete slab floor is poured it desirable to preserve not only (a) the internal threading of the drain collar but also (b) free access to the entire drain collar for the purpose of shimming the same in order to level the drain collar after the floor is poured. It is also desirable to provide for (c) proper sloping of the finished floor proximate the drain strainer in order to achieve desired drainage characteristics and to (d) avoid a plethora of problems commonly encountered during this installation.
The final floor finish is often changed during construction, for example, and the selection of a thicker flooring will require greater depth around the drain. This will necessitate changing of the finished slope about the drain. Provision for slope in the finished floor is often wholly neglected in pouring the slab and burying of the drain during the same is also known to occur on occasion. Another problem associated with this phase of construction is the collision of equipment with the drain thereby displacing the drain from level. Another prevalent problem is that cement finishers often do not finish the slab about a drain to accommodate the finished floor.
It is considered, upon a basis of over thirty-five years experience, that the installation of hub drains during construction involving the pouring of a concrete slab floor is ineluctably and consistently plagued by the problems mentioned above. It is also considered that the only solution to these problems is chipping away concrete about the hub drain which is invariably expensive and consumptive of time.
It is noted that it is a practice of some builders to use forming lumber to block our an area about the drain leaving a rather large hole the entire depth of the slab. This practice adversely affects the integrity of the slab especially below grade. It is also noted that it is a common practice to use foam or insulation wrapped around a drain strainer threaded into the collar in order to enable adjustment of the same after the slab hardens. While preserving the ability to adjust the elevation of the drain strainer this practice neither provides access to the drain collar nor addresses the issue of sloping about the drain.
Discussion of the Prior Art
The following U.S. Patents are considered pertinent to the present invention:
Gerriets discloses a hollow form having an outer cylindrical wall and an inner xe2x80x9cannular wallxe2x80x9d both connected by a top plate, all constructed of thin sheet metal or other xe2x80x9cseverablexe2x80x9d material. The interior sleeve is preferably inclined inwardly from top to bottom to facilitate disposition within the open ends of pipes of varying diameter. A patent two years later issued to Gerriets is also noted which adds an inwardly convex shape to the interior sleeve which here fits about the pipe rather than inside the same.
Currier discloses an annular sleeve of xe2x80x9cnon-water absorbing frangible foamed plasticxe2x80x9d, preferably polystyrene, which is slit, preferably along a diagonal, for reserving an annular space about an upright pipe, including the mouth of a pipe, during pouring of concrete or concrete. Harvey discloses a xe2x80x9ccup-shapedxe2x80x9d device, open at the bottom and closed at the top, possessing a cylindrical outer wall and a shorter cylindrical inner wall which possesses inwardly extending xe2x80x9cfingersxe2x80x9d aligned radially which can be readily broken at intervals along the axial length of each to accommodate varying outer diameters of pipes in positioning of the device about the same.
Izzi, Sr.""s ""universal plastic plumbing joint"" discloses use of an outer sleeve with a smooth exterior wall intended to fit inside a pipe""s open end with internal threading mating with an externally threaded internal sleeve which can be adjusted elevationally for disposition of a drain relative to the level obtained in pouring a slab of concrete, among other uses. Nettel""s ""cleanout extension adaptor"" discloses a similar structure using an externally threaded plug mating an internally threaded cylindrical body which possesses a xe2x80x9csmall thin, lip (extending radially outward) on the top for seating on the top of a cleanout extensionxe2x80x9d. Papp discloses, most pertinently as shown in FIG. 5, use of a disposable sleeve, preferably made of waxed cardboard, which fits snugly inside the open end of an internally threaded pipe and extends upward to provide a cylindrical space above the mouth during pouring of concrete and to keep the internal threading clean during the same.
Hooper discloses a xe2x80x9ccollar for a drain pipe riser . . . for maintaining an annular space aboutxe2x80x9d the riser during pouring of a concrete slab possessing an external cylindrical sleeve and an internal cylindrical sleeve radially spaced apart from the outer sleeve and connected to the same by at least one set of xe2x80x9cwebsxe2x80x9d. The ""drain and cleanout spacer"" disclosed by Foernzler possesses two xe2x80x9ccup-shaped plastic spacers joined by a flexible webxe2x80x9d. Each spacer is simply a circular cover with a downwardly depending cylindrical outer wall dimensioned to fit over the exterior diameter of the mouth of drain strainer and a cleanout port, respectively. It is also suggested that a flag extend upwardly from one cover to provide a visual indicator.
Statement of Need
The prior art reviewed above teaches the use of frangible annular shells for the preservation of an annular space about the top of a pipe during the pouring of a concrete slab thereabout and teaches the use of threaded cylindrical members in extension of a drain plate or strainer with respect to a hub drain. The space reserved about the top of the pipe is not, however, adjustable and hence no accurate provision for sloping of the finished cement about the drain is available.
If a frangible form is deployed to reserve space about a drain hub in order to preserve access to a drain collar fitted in the same the form necessarily creates a void about the collar and the drain hub below the level of the collar. This is considered undesirable in adversely affecting the integrity of the installation in a manner similar to the adverse affect upon the integrity of the slab caused by the practice of using forming lumber about a drain noted earlier. It is considered that while it is desired to preserve access to the drain collar, in addition to preserving the internal threading of the same and the ability to adjust the elevation of the drain strainer typically engaging this threading, creating a void in the slab about the drain below the top surface of the drain collar is also undesirable for structural reasons. Another aspect of the frangible forms known in the prior art is that the form is necessarily destroyed in removal. This is considered to be wasteful at best for both economic and environmental reasons.
It is hence considered that a need therefore exists for a form which will preserve an annular space about a hub drain during pouring of a concrete slab floor about the same which will not create a void below the top surface of the drain collar and which will preserve an annular space about the drain which facilitates sloping of the finished cement floor about the drain. It is further considered that a need exists for such a form which is capable of accommodating changes in finished floor elevation during construction in preserving an annular space about the drain which facilitates sloping of the finished cement floor. And it is considered that a need further exists for such a form which is reusable in order to be conservative of both economical and environmental resources.
Objects of the Invention
The encompassing object of the principles relating to the present invention is the facilitation of proper installation of a hub type drain with a drain strainer which is adjustable in elevation relative to a drain collar seated in the top end of an upright drain pipe with a form preserving both a void about the drain which provides for sloping of the finished cement floor proximate the drain strainer and the integrity of the concrete slab thereabout.
A first auxiliary object of the principles relating to the present invention is a form which preserves a void about a hub type drain which preserves the ability to adjust the elevation of the drain strainer relative to the drain collar during installation of the drain while pouring a concrete slab floor about the drain.
A second auxiliary object of the principles relating to the present invention is a form which preserves a void about a hub type drain which preserves full access to the drain collar during installation of the drain while pouring a concrete slab floor about the drain so that the drain collar may be removed from the top end of the upright drain pipe and shimmed in order to level the drain collar.
A third auxiliary object of the principles relating to the present invention is a form which preserves a void about a hub type drain which possesses a shape relative to the anticipated level of the finished floor and the accordingly desired level of the adjustable drain strainer suited for effecting a proper sloping about the drain strainer with a minimum of time, skill, and expense in finishing the cement floor about the drain.
A fourth auxiliary object of the principles relating to the present invention is a form which preserves a void about a hub type drain which may be elevationally adjusted relative to both the anticipated level of the finished floor and the accordingly desired level of the adjustable drain strainer with a minimum of time, skill, and expense in installation of a hub type drain during pouring of a concrete slab floor about the same.
An ancillary object of the principles relating to the present invention is a form which preserves a void about a hub type drain during pouring of a concrete slab floor about the same which is reusable and thereby both environmentally and economically conservative.
Other objects of the principles relating to the present invention include the avoidance of problems typically encountered during installation of a hub type drain during pouring of a concrete slab floor about the same which are rectified only by chipping out cement about the drain.
Principles Relating to the Present Invention
In meeting the above stated objectives it is suggested that a form comprised of a substantially round rigid plate centrally attachable to the top end of an externally threaded cylinder and possessing means of retaining an annular compressible gasket disposed between the bottom surface of the plate and the top surface of a drain collar substantially concentric with and interior to the periphery of the plate be utilized.
The externally threaded cylinder mates with the internally threaded bore of the drain collar and the top of the cylinder may hence be precisely adjusted with regard to elevation above the top surface of the drain collar. The plate is attached to the top of the cylinder after elevational adjustment and secured to the same preferably with the annular gasket in a state of compression between the bottom surface of the plate and the top surface of the upright drain collar including the periphery of the same. The periphery of the rigid plate extending radially beyond the annular gasket is dimensioned to provide a shallow peripheral void continuous with the void effected by the annular gasket between the top surface of the upright drain pipe and the bottom surface of the plate after pouring of a concrete slab floor about the drain is made.
It is also suggested that means of facilitating release of the form from the void in the hardened concrete slab be provided. The use of a plurality of thrust bolts threaded through the plate in a substantially concentric pattern such that each bolt will contact the top surface of the drain collar which effectively comprises the top surface of the upright drain pipe when sufficiently extended and push the plate away from the same when the thrust bolts are extended further is specifically recommended. As an alternative to bolts it is considered that the plate may be released with the use of several air cylinders each displacing a rod downward with operation of a lever which would also force a thrust rod downward against the top surface of the drain collar seated in the top end of the upright drain pipe.
It is further suggested that the top end of the cylinder be closed and have a central threaded bore through and a plurality of locating projections extending upward therefrom mating apertures through the plate. A single central bolt will then serve to secure the plate to the top of the cylinder after positioning of the plate upon the same by matching the projections with the apertures. After hardening of the poured slab this central bolt may be removed, the thrust bolts or other means of releasing the form utilized to free the plate, and the plate and the annular gasket may then be removed from the resulting cavity. The threaded cylinder is removed from the drain collar with counterclockwise rotation and the adjustable drain strainer is threaded into the drain collar.
The resultant void leaves the top surface of the drain collar entirely free so that the same may be removed and, if desired, shimmed in order to bring into level. The internally threaded bore of the drain collar is protected and an adjustable drain strainer may still be adjusted elevationally. The void effected by the periphery of the plate is continuous with the void above the top surface of the drain collar and dimensioned to allow finishing of the concrete floor about the drain strainer with a proper slope. The entire void, moreover, does not extend below the top surface of the upright drain pipe and the integrity of the concrete slab about the upright drain pipe is maintained.
If the final finished floor elevation is altered during construction with selection of thicker flooring, for example, the form is adjustable with respect to elevation above the drain collar seated in the top end of the upright drain pipe. The threading of the cylinder into the drain collar alone, with or without the plate positioned upon or secured to the same, provides a visual indication of the drain location which will assist in avoiding both accidental burial of the top end of the upright drain pipe during pouring of the concrete and collision with the same during construction. The top of the cylinder, moreover, provides a readily checked and adjustable indication of the elevation desired of the finished cement floor and the use of the form assures that adequate provision for proper sloping about the drain in finishing.
Other advantages and benefits anticipated with use of a form in accordance with the principles relating to the present invention may become evident in a reading of the detailed discussion below, especially if made with reference to the drawings attached hereto.